Neanderthal Inbreeding Made Some Humans Weaker Today

Harmful mutations in Neanderthals’ genome left some humans today with a genetic burden.

Sarah Emerson

Jun 6 2016, 5:07p

Neanderthal, Smithsonian National Museum of Natural History. Image: Flickr/Adam Foster

Nearly 100,000 years ago, a resolute group of Homo sapiens left Africa for the unknown. The impetus and timing of their exodus into the Arabian Peninsula remains controversial, but there’s one thing paleoanthropologists know for sure: We weren’t the only human species to have colonized Eurasia.

Genetic clues indicate that early humans and Neanderthals began to coexist and interbreed almost immediately after the great migration of Homo sapiens out of Africa. Their commingling lives on today in Asians and Europeans who carry the evidence of human and Neanderthal breeding in one to four percent of their genome. How, exactly, the genetic material of Neanderthals manifests in modern populations is the subject of scrupulous debate

A new study published in the journal GENETICS proposes that harmful mutations in Neanderthals’ genome not only made the hominin 40 percent less evolutionarily fit than modern humans, but also endowed some of us with that same genetic burden.

“Neanderthals are fascinating to geneticists because they provide an opportunity to study what happens when two groups of humans evolve independently for a long time—and then come back together,” said lead author Kelley Harris in a statement. “Our results suggest that inheriting Neanderthal DNA came at a cost.” to read more of this article, click here